G20 series GSM-gateways are capable to commutate calls not only to GSM but also to landlines (PSTN) as well as to connect analogue phones. Adding analogue FXO-ports and FXS-ports are as simple as adding GSM ports - by installing extension boards.

Currently, them maximum allowed number of FXO-ports are 4. Number of FXS ports is limited to 40.The maximal number of GSM-channels are 24.

For example, by installing G20 equipped with 24 FXS-ports, 4 FXO-ports and 4 GSM-ports, you will have multifunctional Asterisk-based IP-PBX. It will provide you with all modern IP-PBX features (voice menu IVR, call recording,...) and will commutate 24 analogue desk phones, 4 landlines and 4 SIM-cards.